692
FXUS61 KGYX 240822
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
322 AM EST Sun Nov 24 2024

.SYNOPSIS...
Low pressure will slowly move NE through the Canadian Maritimes
through tonight. High pressure briefly builds in for Monday. A
quick hitting system crosses Tuesday bringing wintry
precipitation across the north and mainly rain south of the
foothills. Brief high pressure crosses southern New England late
Wednesday into Thursday. The next low pressure system tracks
from the Ohio Valley towards New England late Thursday into
Friday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Latest RAP13 surface pressure analysis early this Sunday morning
shows the center of low pressure over Nova Scotia with cyclonic
northwesterly flow prevailing over New England. Nighttime
microphysics satellite imagery shows cloudy skies over the north
and mountains with partly cloudy skies further to the south.
Area webcams indicate that snow continues over the far north and
mountains with the upslope flow and lingering moisture. A few
widely scattered rain or snow showers cannot be ruled out south
of the mountains through this morning though, with latest CAMs
indicating the Mid-coast and towards the Penobscot River
standing the greatest chance. It will otherwise remain a breezy
and cool morning with temperatures hovering near their current
readings.

Vertically stacked low pressure will remain over the Maritimes
today, resulting in continued upslope snow over the north and
mountains. Additional snow accumulations of 1-3" can be expected
over these regions with localized amounts nearing 5" over the
highest terrain and northern Coos county. A lingering PGF
combined with a 50 kt LLJ will result in northwesterly wind
gusts between 25-35 mph with a few gusts nearing 40 mph likely.
Skies will be cloudy over the north and mountains with partly
sunny skies further to the south. Highs will range from the 30s
over the north and 40s south but windchills will generally be
into the 20s and 30s all day.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Low pressure will begin to retreat east tonight, allowing winds
to become more westerly overnight with the PGF gradually
weakening. Despite this, expecting much of the region to remain
mixed through the night with wind gusts up to 25 mph. Lows will
range from the 20s to lower 30s. Snow showers over the north and
mountains will gradually come to an end overnight.

Surface high pressure will briefly build over the area on
Monday, resulting in partly to mostly sunny skies and less wind
than previous days. Highs will range from the 30s to 40s from
north to south with a few spots possibly approaching 50 degrees
in southern NH.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Long Term Update...

Brought in some freezing rain chances for Tuesday morning
across parts of the interior, and especially through the
northern valleys. The window for this would be brief before
changing to either rain or snow, but even light amounts on
untreated roads could be enough to bring some slick travel
across northern valleys. Should the precip move in a little
later in the morning, the concern would be lower with the
daytime insolation warming the low levels. But if the precip
arrives a little earlier, which often happens with WAA systems,
the chances for this period of light freezing rain would be
greater. Either way, by midday the secondary low pressure is
expected to organize, drawing in cooler air through the
atmosphere and allowing for just rain or snow.

The next system for late Thursday through Friday looks to be
coming into better focus, with the GFS and its ensembles coming
more in line with the Euro. The latest Euro run was also a
little less amplified and cooler than the 12z run, but it`s
still too early to draw any conclusions on a rain/snow line
placement trend from just this one run. Either way, confidence
is relatively high and increasing for a system during this
timeframe, with precip type and placement remaining the biggest
uncertainty factors.

Full Discussion...

Overview:
Confidence is increasing in the development of an upper level
flow pattern that will deliver cold air into the central and
eastern CONUS starting around the middle of next week. Recent
runs of global ensembles have been showing strong ridging
building from eastern Siberia across Alaska into western Canada
associated with a -WPO and -EPO. Meanwhile, the NAO is projected
to turn more negative the second half of the week favoring a
storm track along the East Coast. Before the aforementioned
pattern comes to fruition, northern New England will be poised
to receive widespread precipitation from a short wave swinging
across the region Tuesday. Colder air will move in behind this
system with global models suggesting a more robust system
tracking near the Northeast coast around Friday. This late week
system will involve the phasing or non phasing of northern
stream and southern stream energy leading to large variance and
uncertainty in model solutions.

Impacts:
*Wintry precipitation in the foothills to points north could
 bring slick travel Tuesday.

*Low pressure tracking near the Northeast late Thursday and
 Friday could bring wintry precipitation to the region. Large
 variance and uncertainty with this system will likely continue
 for several days, but there is potential for impacts to travel
 during a time of high travel volume.

Details:
A short wave trough swinging through the Great Lakes Monday
night will spawn a surface low that tracks towards the St
Lawrence Valley Tuesday. Several models solutions within the 12Z
suite suggest a secondary coastal low will spin up in the Gulf
of Maine Tuesday. Overall, this looks to be a quick hitting
system with QPF around 0.5 inches. On the other hand,
precipitation types are tricky depending on how cold the area
can get Monday night and the timing of precipitation onset
Tuesday morning. Model soundings suggest that areas from the
foothills northward could see a period of wintry mix Tuesday
morning around the time of the morning commute with mainly rain
along the coastal plain. Depending on the strength of the
coastal low, temperatures will rise above freezing south of the
mountains Tuesday morning with rain becoming the dominant
precipitation type. This system exits Tuesday night with upslope
snow showers continuing in the mountains into Wednesday
morning.

High pressure slides across southern New England late Wednesday
and Thursday morning for mostly dry conditions. Global models
and their ensembles suggest a robust area of low pressure will
track from the Ohio Valley to the East Coast late Thursday and
Friday. One of the sources of this system is currently offshore
the Pacific NW and the other can be traced back to the Bearing
Sea. The phasing or non phasing of these features has produced
run to run and model to model variance in this system. Ensembles
loosely cluster a track along the southern New England
coastline that would favor widespread wintry precipitation
across the area centered on Thursday night into Friday. It will
likely take several days to iron out the evolution of this
system, but it will be one worth watching giving the elevated
travel around the holiday.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
Short Term...MVFR restrictions will persist through tonight at
KHIE with upslope -SHSN at times. VFR conditions are expected at
all other TAF sites. Northwesterly winds will gust up to 35 kts
today before becoming westerly tonight and decreasing to 20
kts. VFR conditions and less wind are then expected on Monday.

Long Term...Mainly VFR into Monday night. Cigs thicken and
lower early Tuesday morning with a brief wintry mix possible
from KLEB to KAUG and points northward before changing to rain
with all rain across the south. This will likely result in MVFR
to IFR Tuesday. Conditions improve Tuesday night into Wednesday
with VFR likely into Thursday.

&&

.MARINE...
Short Term...Gale force northwesterly winds will persist through
today across all waters except for Casco Bay. Winds will become
westerly tonight but gusts will still be hazardous to small
crafts. Winds will then decrease below 25 kts on Monday as high
pressure builds. Seas of 4-7 ft can be expected over the outer
waters with 1-3 ft in the bays through tonight.

Long Term...Winds and seas will drop below SCA thresholds
Monday afternoon into Tuesday morning. Low pressure tracking
west to east across New England into the Gulf of Maine will
bring a return of SCA conditions Tuesday into Thursday morning.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Gale Warning until 6 PM EST this evening for ANZ150>152-154.
     Small Craft Advisory until 6 PM EST this evening for ANZ153.

&&

$$

NEAR TERM...Tubbs
SHORT TERM...Tubbs
LONG TERM...Clair/Schroeter